History of Chinese ethnicity mapped

The first historical map of the Han Chinese ethnic group has been constructed by geneticists in Singapore.

Their research is based on DNA variation across the entire genome, including genetic information taken from 8,200 Han Chinese people across 10 Chinese provinces.

The map provides information about the population history of the ethnic group as it moved northward over time, and will help scientists to identify genes that make some Chinese susceptible to diseases such as diabetes.

The research will also help geneticists to unpick the delicate balance that exists between a population's genes, environment, and diseases.

After their careful examination of the thousands of genetic samples that were used for the study, the researchers were able to distinguish the genetic divergences that have arisen in China over the course of history.

Liu Jianjun, human genetics group leader at the Genome Institute of Singapore (GIS), said that the genome-wide genetic variation observed by the study may be used to infer a person's ancestral origin, including people who are born and raised in foreign countries.

He said that the study provides information that may further the search for genes that confer susceptibility to various diseases.

Edison Liu, the executive director at GIS, said that previous studies on Caucasian populations have provided significant insights into common disorders such as diabetes, high cholesterol, allergies, and neurological disorders, and that his team's study tailors the existing paradigms of disease heritability to closely-related Asian populations.

Chia Kee Seng of the National University of Singapore said that there exist definite differences in genetic architecture between populations, such as have been seen in the Singapore Genome Variation Project.

The team also made progress in determining the genetic basis for psoriasis and systemic lupus erythematosus (SLE), both of which affect autoimmune responses.

Psoriasis causes scaly epidermal patches, and SLE is a disease that affects connective tissue in the heart, joints, lungs, blood vessels, and other organs.

Liu said that his team looked at at least 1,000 psoriasis patients' genes in the course of the study.

He said that the variants causing such autoimmune diseases are very common in patients and very rare in non-patients, and that they can provide information about why certain people develop them.